The present invention relates to a seat cushion; and more particularly, it relates to a seat cushion of the type used in public seating in auditoriums, theaters and the like wherein it is highly desirable that the cushion be resistant to flame or fire. In auditoriums, particularly where smoking is permitted, there is a danger that hot ashes or a match may be unwittingly dropped and land on a cushion, thereby presenting a fire hazard.
Some attempts have been made to produce fire-resistant cushions, such as that disclosed in U.S. Pat. No. 3,813,715, issued June 4, 1974. Such attempts generally rely on incorporating fire-resistant materials, such as asbestos, into the cushion, or they employ means for conducting heat away from localized areas. Either of the above-mentioned methods of producing flame-resistant cushions sacrifices either comfort or economy.
The present invention provides a flame-resistant cushion which includes a conventional frame assembly. An inner foam polyurethane material is carried by a "no-sag" spring structure which is an integral part of the frame. An exterior covering layer of foamed neoprene is integrally bonded to the entire surface area of the top, front, back and sides of the polyurethane core material by means of a carrier sheet so that the neoprene completely encompasses the polyurethane and provides a flame-resistant exterior for the five sides just mentioned. A metal pan is secured to the frame assembly to enclose the bottom of the cushion. and thereby provide a fully-enclosed flame-resistant cushion.
The cushion covering is made by forming a latex water emulsion of neoprene with suitable modifiers and frothing it with air. The frothed emulsion is foamed into a thin layer onto a carrier sheet (such as spun polyester) to form a composite. The composite, cut to shape, is used to line a mold with the foam side in (i.e., the foam contacts the mold surface). Unreacted polyurethane foam is poured into the mold on the carrier. The adhesive properties of the polyurethane cause it to bond with the carrier as it gels, thus forming an integral covering for the spring and frame.
I have discovered that by using a layer of neoprene which is at least three-sixteenths of an inch thick, and which fully surrounds the polyurethane core and is strongly bonded thereto throughout the entire interface, a cushion is provided which is flame resistant. Tests have shown that when the cushion is exposed to flame, the neoprene does not drip away to expose the more flammable polyurethane core. Rather, the neoprene chars and the ash forms a layer which acts as an insulator to retard the spread of flame. Obviously, if the polyurethane is permitted to get hot enough, it will flame; however, the first few minutes after ignition are often critical because it is during this time that a fire either builds up in intensity or dies out. It is during this period that the cushion of the present invention has shown itself to be quite resistant to flaming.
Further, a cushion made in accordance with the present invention has substantial savings in material costs while providing a soft, comfortable cushion.